Backpackers in Titcomb Basin, in Wyoming's Wind River Range.

Ask Me: What’s the Best Ultralight Thru-Hiking Backpack?

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Hi Michael,

I’m looking for a backpack for my Appalachian Trail thru-hike. I am considering some Osprey packs and others. What to you recommend as the best thru-hiking backpack?



Hi Bruce,

Congratulations on your plans to thru-hike the Appalachian Trail, I hope it goes really well for you.

As I wrote in my “Top 5 Tips For Buying the Right Backpacking Pack,” when ultralight backpacking, as you’ll do on a thru-hike, I want a lightweight backpack with minimal features like pockets and zippers. Still, I like the convenience of quick access for some items, like a lid, side, and/or hipbelt pockets for snacks, map, sunglasses, and sunblock, and a mesh front pocket where I can stuff a jacket.

Packs made for ultralight backpacking and thru-hiking typically weigh between two and 2.5 pounds, and have support for carrying 25 to 30 or 35 pounds—and as you probably know, you should only carry the upper end of that weight range on longer stretches of trail where you have several days’ worth of food. Get a pack somewhere between 40 to 60 liters capacity. You’ll want gear that is light and compact. (See all of my reviews of ultralight backpacking gear, backpacking tents, hiking shoes, sleeping bags, and sleeping pads, and my Gear Reviews page for numerous stories with my picks for best gear and tips on buying gear.)

The pack you choose will depend on personal preferences regarding design features, price, weight, and capacity. There are several backpacks that stand out in this category.


Osprey Exos 58 backpack in Glacier National Park.

The 2018 Osprey Exos 58 backpack in Glacier National Park.

For a top thru-hiker pack, especially if you like Osprey, I suggest you look at the Osprey Exos 58 ($220, 2 lbs. 11 oz.) or Exos 48 ($200, 2 lbs. 5 oz.), which have been udpated for 2018. The women’s version is the Eja 58 and Eja 48, introduced in 2018. I’ve used and liked the Exos 58 a lot since it first came out in 2008, including on a four-day, 86-mile backpacking trip in Yosemite National Park and on a weeklong hut trek in Italy’s Dolomite Mountains, and I more recently took the 2018 version of the Exos 58 on a six-day, 90-minute hike through Glacier National Park.

The top-loading Exos and Eja carry 30 pounds or more comfortably thanks to an alloy perimeter frame and a pronounced bell shape that transfer much of the pack weight onto your hips, where you want it, and they have the capacity for weeklong trips and ultralight thru-hiking. Their trampoline-style back panel permits cooling air circulation. At just over 2.5 pounds, they have smart features like good compression, a removable lid, voluminous exterior pockets, and a handy trekking poles attachment on the left shoulder strap.

Read my review of the 2018 versions of the Osprey Exos 58 and Eja 58.

You should also take a look at Osprey’s new-for-2018 “super ultralight” pack, the men’s Levity 60 ($270, 1.9 lbs.)—the women’s version is the Lumina 60 —which Osprey says carries up to 25 pounds. There are smaller sizes, the Levity 45 and Lumina 45 ($250, 1.8 lbs.). Osprey says these packs are definitely for committed ultralighters, primarily thru-hikers who are carrying extremely minimalist kits—for lighter loads than the Exos/Eja.


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The Gregory Optic 58 ultralight backpack in the Grand Canyon.

The Gregory Optic 58 ultralight backpack in the Grand Canyon.

I also like the Gregory men’s Optic 58 and women’s Octal 55 ($210, 2 lbs. 7 oz.), and the smaller Optic 48 and Octal 45 ($190), because they are designed for backpackers who want to go ultralight without switching to a stripped-down style of backpack. I found it comfortable carrying 30 to 35 pounds backpacking the Grand Canyon’s rugged Thunder River-Deer Creek Loop off the North Rim.

These packs sport six external pockets, including two on the hipbelt and a large, stretch-mesh front pocket, and useful features like a quick attachment on the left shoulder strap for trekking poles or sunglasses. Gregory’s attention to comfort in its first ultralight backpack is reflected in the aluminum perimeter wire with an HDPE framesheet and leaf-spring lumbar pad, which distributes most of the pack’s load across the hips and delivers support for carrying 30 to 35 pounds; and the trampoline-style Aerospan suspension, a tensioned, highly ventilated back panel that allows allow air movement across your sweaty back.

Read my review of the Gregory Optic 58 and Octal 55.


The Hyperlite Mountain Gear 3400 Windrider backpack in the Wind River Range.

The Hyperlite Mountain Gear 3400 Windrider backpack in the Wind River Range.

The Hyperlite Mountain Gear 3400 Windrider ($340) weighs just two pounds, has removable aluminum stays and a harness system that I found comfortable carrying 30 to 35 pounds, and is made with waterproof (and practically bulletproof) Dyneema fabric. Its minimalist design features three roomy, exterior mesh pockets and zippered hipbelt pockets, and a roll-top closure with top and side compression for stabilizing under-filled loads. For its weight, it offers unique carrying comfort and capacity for long trips.

Read my complete review of the 3400 Windrider.


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Sierra Designs Flex Capacitor 40-60 backpack.

Sierra Designs Flex Capacitor 40-60 backpack on the Tour du Mont Blanc.

The Sierra Designs Flex Capacitor 40-60 ($200), whose signature feature is a compression system that allows you to alter the pack’s capacity to fit whatever you’re carrying, making it more stable with a small load. At 2 lbs. 9 oz., it’s heavier than others but still a legitimate ultralight backpack, and I’ve found it comfortable hauling 30 to 35 pounds, thanks in part to a sturdier (though still streamlined) hipbelt than is found in some ultralight packs. It has quick, one-zipper access to the main compartment, and five external pockets (lid, side, and hipbelt).

Read my review of the Flex Capacitor 40-60.


REI Flash 45

The REI Flash 45 in Utah’s Dark Canyon Wilderness.

The REI Flash 45 ($149), updated in 2017, is not only a steal, but it sports nice design features for ultralight backpacking, including six external pockets; it also weighs close to three pounds, heavier than others listed here. A steel, internal perimeter frame with one horizontal stay, plus a contoured hipbelt and well-padded shoulder straps make it comfortable carrying 25 to 30 pounds, and REI’s UpLift compression system squeezes the load from the bottom to draw it closer to your hips.

Read my complete review of the Flash 45.


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The ULA Circuit ($235) weighs in at 2 lbs. 9 oz., but it’s spacious at 68 liters, and its roll-top closure extends farther than many competitors, giving you more capacity when needed. With a carbon fiber and Delrin suspension, a dense foam frame and an aluminum stay, it will carry up to 30 pounds comfortably, and the hipbelt and shoulder straps come in multiple sizes for customizing the fit for men or women. ULA’s 210 Robic fabric is highly durable, and the pack has a huge external front pocket.

The Gossamer Gear Mariposa 60 ($215-$260) has more capacity than many two-pound packs, comes in a wide range of torso lengths and hipbelt sizes, and has side pockets made of more-durable fabric, rather than mesh. It has a removable internal frame and seven pockets, while weighing under 2 pounds, and comes in three torso and three hipbelt sizes.


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If you scroll through all of my backpack reviews and my review of the 10 best packs for backpacking, you’ll find other models I really like, but most range from around three-and-a-half pounds to five pounds.

See my “5 Tips For Buying the Right Backpack,” “Video: How to Load a Backpack,” all of my reviews of backpacking gear at The Big Outside.

Good luck with your thru-hike. I’d love to hear what you pick for a pack and how the trip goes for you.



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6 Responses to Ask Me: What’s the Best Ultralight Thru-Hiking Backpack?

  1. Lisa Schofield   |  December 30, 2016 at 12:03 am

    When it comes to backpacks on hiking, I would recommend Osprey Atmos 65 because of its capacity and durableness. Its price is affordable also.
    Thank you for your suggestion and please keep it up.

    • MichaelALanza   |  January 2, 2017 at 9:55 am

      Thanks for the suggestion, Lisa. I’m a fan of the older Atmos 65, which was lighter, as well as the newest update of the Atmos, the Atmos 65 AG. However, that pack is a bit heavier now and really built for carrying heavier loads. That’s why it and the women’s Aura 65 AG are on my list of The 10 Best Packs for Backpacking ( I prefer a lighter pack for thru-hiking or any ultralight or lightweight backpacking.

  2. Regan   |  July 9, 2015 at 3:08 pm

    I’ve got the Talon 44 & Stratos 34. Love both, but am looking for something alittle bigger for some really long hikes. I still want light as I can get tho. Just tried on both the Exos 58 and Atmos AG 65 at the local EMS. The Atmos felt better with more weight compared to the Exos, which makes sense. But I really dug the way both felt. My only gripe with the Atmos is that I hit my head on the metal frame whenever I tilted my head back even alittle bit. I’m a big guy. 6’4″ & 230lbs so I tried on the large. The Exos frame didn’t hit my head at all when looking up. But I loved the way the Atmos hugged my body and carried heavier loads like nothing. So I’m torn. Get the Exos & be able to look up. Lol. Or get the Atmos and be able to carry more better. Hmm.

    • michaellanza   |  July 9, 2015 at 5:26 pm

      Hi Regan, I understand your dilemma, the Atmos AG 65 and Exos 58 are certainly both great packs, but for different purposes. Besides deciding based on how each fits your torso, I think your question comes down to how much weight you intend to usually carry: 30 pounds or less? Go with the Exos. 40 to 50 pounds? You want the Atmos. I suggest you know the weight of your usual gear, food, etc., before making that decision.

  3. Edward Montgomery   |  January 4, 2015 at 5:44 pm

    I used the Exos 58 on the Camino de Santiago last April- GREAT PACK!

    • michaellanza   |  July 9, 2015 at 5:30 pm

      Yes, Edward, I’m sure it was excellent for the Camino. I’ve heard really good things about that trek.

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